Microsoft Windows Server 2025 Update Version OS Build 26100.33158

KB5099536 for Windows Server 2025 (OS Build 26100.33158) includes the latest security fixes, non-security improvements from KB5094125, and a servicing stack update KB5101372. It also adds PQC TLS 1.3 support, RDP SHA-2 thumbprints, and Secure Boot certificate deployment improvements. Reference IDs: CVE-2026-56155, CVE-2025-59287.

• Adds support for hybrid post-quantum cryptography (PQC) key exchange in TLS 1.3 to strengthen secure network connections.
• Adds support for composite cryptographic formats that combine traditional and post-quantum algorithms in a single signature or key.
• Introduces automatic detection of insecure DKM container ACL configurations in AD FS with an opt-in remediation mechanism for stronger permissions.
• Enforces TDI transport registration requirements; apps using sockets over unregistered third-party TDI transports might stop working after this update.
• Adds SHA-2 certificate thumbprint support for trusted RDP publishers and recommends migrating to SHA-256 or stronger to reduce phishing risk.
• Includes additional high-confidence device targeting data to expand Secure Boot certificate deployment coverage.

• Fixes third-party apps using OLE Automation with Microsoft Office that could fail to launch Office or open documents after KB5094125.
• Improves startup performance for Hyper-V-isolated Windows Server containers.
• Improves reliability of the Windows Event Log service on event collector servers forwarding to custom log channels.
• Fixes File Explorer OneDrive shortcut failures when File Explorer runs in administrative mode.
• Changes hotkey unregister and cleanup behavior for built-in Windows experiences that rely on previous hotkey lifecycle behavior.
• Improves connections to shared network resources, including unauthenticated null session connections.
• Fixes a Windows stop responding issue in certain situations.
• Fixes a graphics kernel driver memory leak that affected graphics-intensive virtual machines and reduced excessive memory usage.
• Fixes Recycle Bin confirmation dialogs showing an internal file name instead of the original file name when permanently deleting a file.

• Adds support for hybrid post-quantum cryptography (PQC) key exchange in TLS 1.3.
• Adds support for composite cryptographic formats combining traditional and post-quantum algorithms.
• Adds SHA-2 certificate thumbprint support for trusted RDP publishers.
• Introduces automatic detection of insecure DKM container ACL configurations in AD FS with opt-in remediation.

• Some built-in Windows experiences that rely on previous hotkey lifecycle behavior might temporarily stop responding to certain keyboard shortcuts after the input changes.
• Applications using sockets over unregistered third-party TDI transports might stop working after installing this update.
• WSUS does not display synchronization error details within its error reporting after KB5070881 or later updates.

• Updated Windows Server 2025 container base images (nanoserver, servercore, and windowsservercore) are available through Microsoft Container Registry; pull the latest image tag to get the startup performance improvement.
• Microsoft recommends migrating RDP file security to SHA-256 thumbprints or stronger algorithms as soon as possible.
• Secure Boot certificates are being updated through Windows Update over the coming months for supported PCs and non-managed business devices.
• KB5101372 is the servicing stack update included with this release.
• If you have already installed previous updates, only the new updates in this package will be downloaded and installed.

• Windows release health dashboard
  https://learn.microsoft.com/windows/release-health/
• Secure Boot certificate expiration and CA updates
  https://learn.microsoft.com/windows/security/operating-system-security/secure-boot/certificate-expiration-ca-updates
• Windows Server 2025 release health
  https://learn.microsoft.com/windows/release-health/status-windows-server-2025

Product Information

Vendor: Microsoft

Product: Windows Server 2025

Product type: Software

Application category: Utilities

Platform: Windows

Version: OS Build 26100.33158

Vendor release date: Jul 14, 2026

Original release notes: View on vendor site

Published on updatealert.io: Jul 16, 2026

Description: Server operating system for next-generation on-premises and hybrid workloads.